I presume you got the Colemak keyboard by running or loading some driver to change the keys to Colemak. That process then changes the digital signals from the keyboard so that instead of "e" you see "f," for example. What that means, however, is that combination keys like Command+shift+P don't see the "P" on your keyboard because it's been remapped to a where the "R" key is on a standard QWERTY keyboard. If your driver passes along CMD and other function keys without changing them, you might be able to try CMD-shift-semicolon on Colemak, as the ";" is where the "P" is physically. ON the other hand, if the driver maps everything and doesn't pass the raw key data at all, then you probably can't get ANY of the function+keys to work. Based on your comment, I suspect that is what is happening, in which case the only solution is to remove the Colemak driver.